This is a completely new holographic technology for fabricating extremely efficient antireflection coatings. The holographic coating can be used on any optical surface. When used alone it can reduce unwanted reflections to a fraction of one percent. A holographic coating can be fabricated to be narrow bandwidth (5-50nm) or extremely broad band. This technology may be used in conjunction with conventional antireflection coatings so that a surface may be made virtually reflection-free. The theory of these holographic antireflection coatings is relatively straightforward. Optical surfaces reflect light. The light which is reflected is of a certain phase and amplitude. If a holographic film is applied to such an optical surface, there will still be a reflection off the surface, as well as a reflection off the hologram. If, however, the hologram is fabricated such that its reflection has the same intensity (amplitude) and is 180 out of phase with the reflection off the optical surface, then the reflections off of the two surfaces (i.e., the optical surface and the hologram) cancel. The result is cancellation of the reflection by interference. Results obtained during the Phase I contract validate this theory. This technology has several attractive features. It is well known that holograms can be fabricated to either narrow band or broad band, and it is easy to keep the efficiency low. Because the index modulation in the fabricated hologram is sinusoidal by nature of the fabrication, the device performance is far superior to multilayer systems. The fabrication techniques are in principle extremely simple. In many cases, the surface itself can be used as the substrate. The holographic film is applied directly, ensuring faithful conformity of the holographic structure with the film surface. Thus, the Phase II work will be develop techniques, with the appropriate apparatus, for making these Holographic Antireflection Coatings. This technology is applicable to literally dozens of commercial applications. Anywhere unwanted reflection exists a simple coating to reduce or eliminate that reflection is appropriate. Applications include: windows and windshields of all kinds (helicopters, aircraft, military craft,
Keywords: Holographic Antireflection Coatings
